A pyrrole compound having a substituted sulfonyl group at the 1-position (hereinafter to be referred to as a sulfonylpyrrole compound) is useful as an acid secretion inhibitor (proton pump inhibitor), and a therapeutic drug for neoplastic diseases and autoimmune diseases (patent documents 1-3).
For example, patent document 1 describes, as a compound having an acid secretion inhibitory activity, a compound represented by
wherein r1 is a monocyclic nitrogen-containing heterocyclic group optionally fused with a benzene ring or heterocycle, and optionally having substituent(s);r2 is an optionally substituted C6-14 aryl group, an optionally substituted thienyl group or an optionally substituted pyridyl group;r3 and r4 are each a hydrogen atom, or one of r3 and r4 is a hydrogen atom, and the other is an optionally substituted lower alkyl group, an acyl group, a halogen atom, a cyano group or a nitro group; andr5 is an alkyl group, or a salt thereof.
Patent document 2 describes, as a production method of a sulfonylpyrrole compound, the following method using pyrrole-3-carboxylate ester:
wherein each symbol is as described in patent document 2.
Patent document 3 describes the following production method of a sulfonylpyrrole compound:
wherein each symbol is as described in patent document 3.
Patent documents 4 and 5 describe, as a production method of a sulfonyl chloride compound, a method including reacting pyridine-3-sulfonic acid with phosphorus pentachloride in a solvent of phosphorus oxychloride or toluene to give pyridine-3-sulfonyl chloride. Patent document 6 describes a method including reacting pyridine-3-sulfonic acid with phosphorus pentachloride without solvent to give pyridine-3-sulfonyl chloride.